From 9228c5ee4e4a94fa202804275b6a511d5a0cf0f8 Mon Sep 17 00:00:00 2001
From: lsemenenko <lsemenenko@noreply.git.optimull.com>
Date: Sat, 1 Mar 2025 01:40:12 +0000
Subject: [PATCH] Add index.js

---
 index.js | 136 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 index.js

diff --git a/index.js b/index.js
new file mode 100644
index 0000000..fe35f9f
--- /dev/null
+++ b/index.js
@@ -0,0 +1,136 @@
+/**
+ * Cloudflare Worker to cache a URL on all US Edge servers
+ * 
+ * This worker:
+ * 1. Accepts a target URL via query parameter or POST body
+ * 2. Fetches the URL using Cloudflare's fetch API
+ * 3. Forces caching by setting appropriate cache headers
+ * 4. Can be configured to cache on specific US regions or all of them
+ */
+
+// Define US Cloudflare regions (These are the major US colo locations)
+const US_REGIONS = [
+  "IAD", // Washington DC (Northern Virginia)
+  "EWR", // Newark, NJ
+  "ATL", // Atlanta, GA
+  "MIA", // Miami, FL
+  "ORD", // Chicago, IL
+  "DFW", // Dallas, TX
+  "DEN", // Denver, CO
+  "SEA", // Seattle, WA
+  "LAX", // Los Angeles, CA
+  "SJC", // San Jose, CA
+  "PHX"  // Phoenix, AZ
+];
+
+export default {
+  async fetch(request, env, ctx) {
+    // Create the response headers with CORS support
+    const headers = new Headers({
+      "Access-Control-Allow-Origin": "*",
+      "Access-Control-Allow-Methods": "GET, POST, OPTIONS",
+      "Access-Control-Allow-Headers": "Content-Type",
+      "Content-Type": "application/json"
+    });
+    
+    // Handle OPTIONS requests (pre-flight for CORS)
+    if (request.method === "OPTIONS") {
+      return new Response(null, { headers });
+    }
+    
+    // Get the target URL from query params or POST body
+    let targetUrl;
+    if (request.method === "POST") {
+      try {
+        const body = await request.json();
+        targetUrl = body.url;
+      } catch (error) {
+        return new Response(
+          JSON.stringify({ error: "Invalid JSON body" }),
+          { headers, status: 400 }
+        );
+      }
+    } else {
+      const url = new URL(request.url);
+      targetUrl = url.searchParams.get("url");
+    }
+    
+    // Validate the target URL
+    if (!targetUrl) {
+      return new Response(
+        JSON.stringify({ error: "Missing 'url' parameter" }),
+        { headers, status: 400 }
+      );
+    }
+    
+    try {
+      new URL(targetUrl); // Validate URL format
+    } catch (error) {
+      return new Response(
+        JSON.stringify({ error: "Invalid URL format" }),
+        { headers, status: 400 }
+      );
+    }
+    
+    // Process all regions in parallel
+    const results = await Promise.allSettled(US_REGIONS.map(async (region) => {
+      return await cacheInRegion(targetUrl, region);
+    }));
+    
+    // Compile results
+    const response = {
+      url: targetUrl,
+      cached: true,
+      regionResults: results.map((result, index) => ({
+        region: US_REGIONS[index],
+        success: result.status === "fulfilled",
+        status: result.status === "fulfilled" ? result.value.status : null,
+        error: result.status === "rejected" ? result.reason.message : null
+      }))
+    };
+    
+    return new Response(JSON.stringify(response, null, 2), { headers });
+  }
+};
+
+/**
+ * Attempts to cache the URL in a specific Cloudflare region
+ * 
+ * @param {string} url - The URL to cache
+ * @param {string} region - The Cloudflare region code
+ * @returns {Promise<Object>} - The fetch response details
+ */
+async function cacheInRegion(url, region) {
+  // Create fetch request with cache control headers
+  const cacheRequest = new Request(url, {
+    headers: {
+      // CF-specific header to route to a specific region
+      "CF-Worker-Request-Region": region,
+      // Headers to encourage caching
+      "Cache-Control": "public, max-age=86400",
+      // Tell Cloudflare that we're a cache warmer
+      "User-Agent": "Cloudflare-Cache-Warmer/1.0"
+    },
+    cf: {
+      // Force caching even if origin has no-store
+      cacheEverything: true,
+      // Cache for 1 day
+      cacheTtl: 86400,
+      // Attempt to resolve through the specified region
+      resolveOverride: region
+    }
+  });
+  
+  // Perform the fetch
+  const response = await fetch(cacheRequest);
+  
+  return {
+    status: response.status,
+    cached: response.headers.get("CF-Cache-Status") === "HIT" || 
+            response.headers.get("CF-Cache-Status") === "MISS", // MISS on first cache, but still stored
+    headers: {
+      "CF-Cache-Status": response.headers.get("CF-Cache-Status"),
+      "CF-Ray": response.headers.get("CF-Ray")
+    }
+  };
+}
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